The demand for mild, environmentally friendly surfactants has been steadily rising. In general, most toilet bar compositions contain surfactants based on petro chemicals. Since these materials often have handling, storage and environmental hazards associated with them, it would be most desirable to use surfactants which are instead derived from agriculturally grown materials, such as carbohydrates. These naturally occuring compounds represent a source of renewable raw materials that are readily available, inexpensive, biodegradable, aquatically favorable and optically pure.
(Alkyl glycosid)uronates are known to be prepared by catalytic air oxidation of alkyl glycosides over a platinum or palladium catalyst in alkaline aqueous solution according to the following equation: ##STR1##
U.S. Pat. No. 2,562,200 to Mehltretter and U.S. Pat. No. 2,845,439 to Corn Products Refining Company, both teach the above identified process using short chained sodium(alkyl glycosid)uronates in which R is methyl, ethyl or hydroxyethyl. European Patent No. 0,326,673 and German Patent No. 3,803,465 to Ripke et al., also teach the above-identified process which is directed towards long chained sodium(alkyl glycosid)uronates in which R is greater than 8 carbons.
These known processes suffer from the distinct disadvantage of being performed under dilute reaction conditions (3 to 6% alkyl glycoside in 85 to 97% water) resulting in low product output and therefore rendering the process uneconomical. In fact, higher concentrations of alkyl glycoside (&gt;10%) cause a retardation of reaction velocity, and yields are diminished (K. Heyms and H. Paulsen, Adv. Carbohyd. Chem., 1962!, V. 17, p. 176).
In addition to failing to teach the specific process of the invention, none of these references or other prior art of which applicant is aware of teaches or suggests the use of these surfactants in toilet bar compositions.
More specifically, while Ripke 3,803,465 or EP 0,326,672 suggests that the compounds of the invention may be suited for detergent or cleanser applications, however, there is no suggestion to use them in toilet bar compositions. It must be recalled that the surfactants which are anionic would be classified as generally being harsh to the skin. Thus, while one of ordinary skill in the art might contemplate use of these anionics in detergent compositions where there would be no real direct contact with the skin, such a person would be especially disinclined to formulate the anionic surfactant in a toilet bar where the bar is intimately rubbed by the consumer against the skin. It is only after applicants ran zein tests and discovered the surfactant to be relatively mild on skin that it might even dawn to one of ordinary skill in the art to formulate the surfactant in a bar. Further, the data present in the subject specification cannot be used in making such an assessment.
In the parent of the subject application, the Examiner cited a washing cleanser patent (U.S. Pat. No. 5,132,037) in combination with several chemical abstract references relating to uses of uronic acids. On particular, the Examiner noted CA 101:97490Z, relating to the use of uronic acid for smoothing skin and eliminating flaking. The chemical abstract references, however, all relate to uronic acids, not surfactant derivatives. It is anionic surfactants which are known to be harsh and there would have been no motivation, let alone a teaching, to prepare a surfactant from the acid.
Finally, WO 9302092 to Zschimmer & Schwarz teach galacturonic acid derivatives similar to the compounds of the invention. This application was published after the filing date of the priority date to which the subject application is entitled and is not available as prior art.
Accordingly, it is one object of the invention to provide a novel toilet bar composition comprising the surfactants of the invention.
Another object of the invention is to provide such a bar that is mild to the skin and has good lathering and tactile properties.
It is yet another object of the invention to provide a new and improved process for the manufacture of (alkyl glycosid)uronates, preferably alkali metal (alkyl glycosid)uronates such as sodium(alkyl glycosid)uronates.
It is a particular object of the invention to prepare alkali metal (alkyl glycosid)uronates in good yield, high purity and desirable color within a commercially feasible economical output.
These and other objects of the invention will become more apparent from the detailed description and examples that follow.